Patent Literature 1 describes the basic configuration and the principle of operation of a typical piezoelectric power generator in related art, which converts kinetic energy that is externally input into electrical energy by using a piezoelectric element to extract electric power and supplies the electric power to an electric storage device. Setting of a free vibration frequency of a free vibration member in a region in which the frequency components of an exciting acceleration frequently occur is described in Patent Literature 1. In addition, Patent Literature 1 indicates that, when the frequency components of the acceleration are known, the dimensions of the element can be adjusted to set the natural frequency in an appropriate region in order to maximize the output.
In the piezoelectric power generator described in Patent Literature 1, a large change in stress is momentarily applied to the piezoelectric element in response to an instantaneous impact that is exerted to output large electric power. However, in order to continuously extract stable electric power, it is necessary to continue vibration and to use a relatively large rectifier and/or capacitor having a higher dielectric strength and/or connect multiple components, thus increasing the number of components or increasing the size of the generator. In addition, since it is necessary to exert the kinetic energy to all the piezoelectric elements, there is a problem in that the stress is dispersed to decrease the generation efficiency.    Patent Literature 1: Japanese Patent No. 3170965